Chemical induction of gene expression is a regulatory tool in nature and in biotechnology for constructing, studying, and engineering biological systems. Inducible promoters and riboswitches found in nature dynamically control metabolism and cellular communication in response to intracellular and environmental signals. Many of these natural systems have been repurposed in biotechnology. However, these systems are restricted to a limited set of existing and well-characterized biological sensing capabilities; are often constrained for use in particular organisms; and may be challenging to functionally decouple from native cellular regulation. Efforts to expand this natural chemical diversity have included significant advances in the engineering of synthetic riboswitches, which can incorporate novel RNA sensors, or aptamers, generated de novo through in vitro selection and operate through varied RNA regulatory mechanisms. See for example, Chang et al. (2012) Current Opinion in Biotechnology 23(5):679-688.
There is a need, therefore, to develop aptamers for gene regulatory systems that can control the expression of specific target genes in vivo in response to effector molecules.